Equatorial Sundial construction (kits?)

[Colin WhittakerParticipant @colinwhittaker20544]

Conventional horizontal and vertical sundials begin to struggle close to the equator where the sun's midday position can be both to the North and to the South depending on the season. Therefore I'm looking at an older design, https://en.wikipedia.org/wiki/Sundial and check out the sundial in the Singapore Botanical Gardens.

The time is read off a semicircular scale with equidistant hours marked every 15 degrees with the gnomon mounted through the axis of the semicircular scale, perpendicular to the same and parallel to the rotational axis of the earth.

So, my question. Is there a way to engrave a scale on the inside of a 40cm diameter curved brass plate? Perhaps someone makes kits?

Thanks, Colin 7.76 deg North

Edited By Colin Whittaker on 07/07/2021 11:50:52

Edited By Colin Whittaker on 07/07/2021 11:53:38

[Colin WhittakerParticipant @colinwhittaker20544]

[Michael GilliganParticipant @michaelgilligan61133]

Not kits, Colin … but have a look at this: **LINK**

http://www.richardkell.co.uk/sundials.htm

You may pick-up some clues.

I have a similarly styled one, by Simon Higgon, so let me know if you need any close-up photos.

MichaelG.

.

Edit: Corrected the fecit of mine 

Edit: __ Mine is very much like this one:

https://www.waymarking.com/waymarks/WMM6NY_Equatorial_Sundial_Horniman_Gardens_London_Road_Forest_Hill_London_UK

Edited By Michael Gilligan on 07/07/2021 12:02:47

Edited By Michael Gilligan on 07/07/2021 12:07:19

[Michael GilliganParticipant @michaelgilligan61133]

Useful link: **LINK**

https://www.blocklayer.com/sundial-equatorial.aspx

MichaelG.

[Martin KyteParticipant @martinkyte99762]

Engrave a flat strip and then roll it into a semicircle.

The Merlin Band Clock bands are made like that although in that case the strip ends up as a full circle.

regards Martin

[Colin WhittakerParticipant @colinwhittaker20544]

So …

1) trial bend

2) then check radius

3) then engrave a new one

4) then rebend and hope to achieve the same radius

Thanks all.

[Martin KyteParticipant @martinkyte99762]

No, roll it into a semicircle. As in using a set of rolls. That way you can approach the chosen radius by gradually adjusting the third roller.

regards Martin

[Colin WhittakerParticipant @colinwhittaker20544]

So I can't use a wooden former to bend the brass to.

I've got to use a set of rollers. That sounds like aother project before I can start.

Thanks for pointing that out Martin.

Colin

[duncan webster 1Participant @duncanwebster1]

make the wooden former to the finished size, bend the brass, measure the actual radius, make the former a bit smaller, bend it again and so on

[Michael GilliganParticipant @michaelgilligan61133]

Just found this link in my old notes : **LINK**

https://www.the-saleroom.com/en-gb/auction-catalogues/andrew-smith-and-son/catalogue-id-srandr10074/lot-a68bcea4-5580-49bc-a258-a81900f1a95b

… some useful photos of a Higgon equatorial

MichaelG.

.

Edit: __ unfortunately, mine doesn’t have the EoT device 

Edited By Michael Gilligan on 07/07/2021 13:39:27

[Martin KyteParticipant @martinkyte99762]

Posted by Colin Whittaker on 07/07/2021 13:12:42:

So I can't use a wooden former to bend the brass to.

I've got to use a set of rollers. That sounds like aother project before I can start.

Thanks for pointing that out Martin.

Colin

Of course you can. I was just saying how I would do it. You only asked for suggestions.

regards Martin

[Colin WhittakerParticipant @colinwhittaker20544]

Martin,

Thanks for clarifying.

Michael,

Integrating the EoT is interesting. My initial plan is for a correction plate and a manual correction but the EoT shadow plates or spindles do look elegant.

Colin

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